How to Iterate Over Characters in Ruby: Simple Guide

In Ruby, you can iterate over characters in a string using the each_char method, which runs a block for each character. This method lets you process or print each character one by one easily.

Syntax

The basic syntax to iterate over characters in a string is using each_char method followed by a block. Inside the block, you get each character one at a time.

• string.each_char { |char| ... } - runs the block for each character
• char is the variable holding the current character

ruby

string.each_char { |char| 
  # code using char
}

Example

This example shows how to print each character of a string on its own line using each_char.

ruby

word = "hello"
word.each_char { |char| puts char }

Output

h
e
l
l
o

Common Pitfalls

A common mistake is trying to use each directly on a string, which does not work because strings are not arrays. Always use each_char to iterate characters.

Also, avoid modifying the string inside the iteration as it can cause unexpected behavior.

ruby

wrong = "test"
# wrong.each { |c| puts c } # This will cause an error

# Correct way:
right = "test"
right.each_char { |c| puts c }

Output

t
e
s
t

Quick Reference

Here is a quick summary of methods to iterate over characters in Ruby strings:

Method	Description
each_char	Iterates over each character in the string.
chars.each	Converts string to array of characters, then iterates.
split("").each	Splits string into characters array, then iterates.

Key Takeaways

Use the each_char method to iterate over characters in a Ruby string.

Do not use each directly on strings; it causes errors.

You can also convert the string to an array of characters with chars or split before iterating.

Avoid changing the string while iterating over its characters.